Can I Use Wilton Columns Without A Separator Plate?

I rarely have to do those old school stacked with columns cakes, but I have one this weekend. Last time I think I bought columns that were tapered at the bottom and I stuck them right in the cake and used them as the support. I just went to the store and all they had were the ones that you need all the separator plates for. I am not about to spend $40 on plates!!

I was thinking of cutting my dowels to 4" (cake height) plus 3" (column height) - so 7" total, and then just balancing the top tier on top of the dowels, but having the columns over the dowel, looking like they are giving support. Sorry if that is confusing.

Is this a terrible idea? I think with a steady table we should be fine ....

Anyone have any other ideas? I should also mention that Michaels didn't even have square separator plates, only round so the plates really aren't an option.